This invention relates generally to ribbon storage devices and more particulary to apparatus for producing uniform ribbon pleats within the storage compartment.
Cartridges for storing inked ribbon in random pleats or folds are well known. The ribbon is often an endless loop that is being concurrently stored and withdrawn. Usually the ribbon is forced or stuffed into the cartridge storage compartment by a pair of feed rolls frictionally gripping the ribbon so that the ribbon forms random bights or folds. No attempt is made to guide or position the pleats which, as a result, are randomly directed within the storage compartment by the impedance and pressures of previously stored ribbon.
Because of the randomness, the ribbon does not progress uniformly through the compartment but rather forms in clumps of folds. These clumps are tied in a meander and often become entrapped behind later-formed ones. Significantly varying withdrawal tension then results. This randomness also results in compaction pressures which vary over a wide range, and create low density storage pockets within the compartment, resulting in inefficient use of the storage volume. At times entanglements occur which even require premature discard of the cartridge.
Because of the wide variation in compaction pressures resulting from randomly plicated ribbon, storage compartments are usually formed with increasing cross-sectional area as the ribbon leaves the feed rolls to relieve compaction pressure. This technique has been used to decrease the withdrawal tension required and to make the tension more uniform. Thus, the irregular configuration of the storage compartment adds to the deficiences previously mentioned.
A previous effort to provide for the storage of uniform ribbon plicae within a compartment is shown in U.S. Pat. No. 2,685,357. This patent describes various techniques of including reciprocating guide elements within the compartment to form the bights uniformly across the chamber. Cranks or gear and rack are used to operate the necessary guiding pins within the compartment. Although the patented apparatus accomplishes highly efficient and desirable ribbon storage, the added structure to perform the packing increases the cost.
In U.S. Pat. No. 3,871,507, no attempt is made to produce uniform pleats in the ribbon, but there is disclosed structure for clearing the ribbon as it leaves the feed rolls and thereby to induce improved packing of the ribbon within the chamber. This is accomplished by using eccentrics to alternately move each of a pair of stripping fingers to push the ribbon from the feed roll surfaces.
Other U.S. Pat. Nos. ilustrative of the random, irregular stuffing of ribbons into storage chambers are 4,053,040; 3,989,132 and 3,814,231. No sturcture is shown in these disclosures that is capable of producing ribbon plicae having uniform length and which are stored in an ordered arrangement.